WHERE THE SEA GETS ITS COLOUR.

Auckland Star, Volume LXIX, Issue 226, 24 September 1938, Page 24 (Supplement)

WHERE THE SEA GETS ITS COLOUR.

Many readers, when spending a holiday at the seaside, will hare noticed the rarying colours of the sea. We generally think of the sea as green, and often it does appear that colour. But in some parts it looks yellow and at other times grey or almost black.

Why is it that the water shows such varied colours? The colour of the sea is due to many causes. When it is grev and dark the colour is due to the reflection in the water of dark clouds abore. Many of the rariations of colour, however, are due to small particles of solid matter in the water and to microscopic animals and plants.

The saltness of the sea also has something to do with its colour. It is bluer where the saltness is greater, and inland seas, like the Mediterranean, being salter than the open ocean are a richer and deeper blue.

In the Arctic and Antarctic, owing to the fresh water from melting ice, the sea is less salt and the colour greener. The green is due partly to microscopic life in the water and partly to the reflected light of the blue sky mingled with the yellowish shades of 'sand and rock thrown up from the sea bottom.

A German chemist has discovered recently that the blue of the sea is due to some extent to the presence of dissolved copper compounds. Copper sulphate, or bluestone as it is called, is blue, and the scientist believes that just as this substance dissolved in water makes the liquid blue, so copper compounds in sea water give it a blue tinge.

Where the water is shallow, as on a sandy, sloping beach, it looks yellow owing to the colour of the sand being reflected up.

Ship Aboyf